I am a guest there, but I am also expected to act as a backup photographer independent of the main guy. I have no wedding experience, but have no way to get out of this. I do not want to take too much equipment to Siberia. My questions are:

2. Should I buy any extra lighting gear in addition to my 580EX-II: a second flash, reflector, soft box, etc.? (Please keep in mind I am not to get in a way of the main guy.)

3. If I were to invest in one extra lens, what lens should I consider? The budget is under $2,000. (I would prefer to avoid lenses scheduled or rumored to be upgraded soon: 24-70L, 35L, or 85L). Should it be wide like 24L or tele like 100L or 135L? Or something simpler perhaps more than one?

4. I have the Gitzo GT3541LS tripod with the Arca Swiss Z1 ballhead, but taking it there and using it at the wedding may be too hard. I am planning to take a monopod with a small ballhead instead. Is this the right choice?

I have extra batteries and memory cards. No second body. Thanks for your advice.

Looking at his web site, I think he'll cover the long focals / shallow focus stuff all right.

This leaves you with a couple of options:

1. go ultra-wide ; given your user name I think you should be comfy working in close quarters using the 17-40; complete with the 50/1.4, 24-105 and flash (slow shutters + second curtain)

2.go B/W ; if you start out thinking B/W from the moment you put your 5D to your head you'll be in a different pre-visualisation mode; journalistic B/W with the 17-40 (mostly 30-40) and lets you get away with blowing highlights. Complete with the Zeiss (fabulous bokeh), 24-105, maybe the 580.

In all cases I would leave the 70-200 (he's already covering that part and big whites scare the crap out of people), 1 of the 50's, both 'pods.

For the rest, don't forget to pack the extension cord to get a different angle for your flash, and a LumiQuest Promax Softbox III (at just over 30$, a no-brainer)

If you're looking to burn cash :

430EXII : smaller and lighter than the 580, and lots cheaper (though not as cheap as the late 420EXII)

the new 40 pancake : makes your gear less obtrussive, and gives you a nice WA